1. Field of the Invention
The present invention relates to reclosable plastic bags of the type in which perishable food products and other goods are packaged for sale to consumers in retail outlets. More specifically, the present invention relates to reclosable plastic bags which are concurrently manufactured and filled with a consumer product on a horizontal form-fill-and-seal (FFS) machine, wherein a plastic interlocking zipper for each bag is disposed longitudinally relative to the direction of motion of the thermoplastic sheet material used to form the reclosable bags on the FFS machine.
2. Description of the Prior Art
The present invention relates to improvements in the package-making art and may be practiced in the manufacture of thermoplastic bags and packages of the kind that may be used for various consumer products, but which are particularly useful for food products which must be kept in moisture- and air-tight packages, free from leakage until initially opened for access to the product contents, which packages are then reclosable by zipper means to protect any remainder of the product therein.
The indicated art is fairly well-developed, but nevertheless remains open to improvements contributing to increased efficiency and cost effectiveness.
The present invention relates more particularly to the production of reclosable plastic bags which are concurrently manufactured and filled with a consumer product on a horizontal FFS machine. In this regard, U.S. Pat. No. 4,589,145 shows a method of and apparatus for packaging a block-shaped product, such as cheese, into a wrapped envelope package, with material especially adapted for said packaging, wherein a bottom face of the product article is engaged on a panel area of the wrapper sheet, which sheet has extended portions that are wrapped about the article and sealed across the top face of the article. One of the portions of the wrapper sheet has a reclosable zipper and a web portion alongside the zipper which is adapted to be severed or ruptured to provide a mouth opening for access to the article within the package, the mouth opening being reclosable by the enclosed zipper. The zipper may be provided with structure to prevent its being pulled open during the wrapping and sealing of the wrapper about the article. The web portion may have guidance for severing or rupturing the same when access into the package is desired.
In U.S. Pat. No. 4,876,842, another method of and apparatus for packaging product masses in an FFS machine, wherein a continuous length of packaging film is joined in running relation by a continuous length of separately formed plastic reclosable fastener assembly having interlock profile strips spot-sealed together at package-length intervals, are shown. The co-running fastener strip assembly and the packaging film are oriented so that the spot seals of the strip are located in alignment with the spaces between the product masses on the film to ensure that the fastener strip assembly will be cross-sealed at the spot seals when the film is cross sealed between the product masses to provide individual packages. The orienting may be effected by an indexing arrangement including sensor response to index marks on the film and the fastener assembly.
The present invention is an improvement over those disclosed in these prior-art U.S. patents.